Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false. The description adds substantial behavior beyond those annotations: maximum 31-day window, up to 1000 points, latest revision/run wins, rejected and suspect rows are excluded, unreviewed rows retain quality metadata, provenance preservation, unit conventions, and returned freshness metadata. No contradiction with annotations is present.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The purpose is front-loaded in the first sentence, and each subsequent sentence adds routing, constraints, provenance rules, or units. However, the description is dense and includes several prescriptive warnings that make it longer than the minimum needed, even though most content earns its place for a complex history tool.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given a nested query object, zero schema parameter descriptions, and no output schema, the description supplies enough context to call the tool correctly: it covers source/var distinctions, forecast spot requirements, time-window and point limits, row-quality filtering, provenance expectations, units, and the shape of returned metadata. Missing enumerations of source/var values are acceptable in an open-world environmental data tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With schema description coverage at 0%, the description must carry parameter meaning, and it largely does: it explains source and var, specifies that forecast source uses forecast:model and requires spot, mentions the 31-day window, and caps points at 1000. It does not fully elaborate every nested field such as from/to formatting or the spot pattern beyond the schema, so it stops short of full compensation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: 'Read stored observations or forecast history for source and var.' It then differentiates from the sibling tool by saying 'For chop history or trends use get_chop_history with a verified spot ID.' It also clarifies the forecast-source variant requiring spot and forecast:model, so an agent can distinguish this tool from adjacent history and observation tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives explicit routing guidance: use get_chop_history for chop history or trends with a verified spot ID. It also states when the forecast-source mode applies: 'Forecast source uses forecast:model and requires spot.' Additional constraints such as the 31-day maximum window and 1000-point cap further define appropriate use.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.